Drosophila
9032
225585378
2008-07-14T12:46:48Z
Mark-mitchell-aldershot
3401544
{{Taxobox
| name = ''Drosophila''
| image = Drosophila melanogaster - side (aka).jpg
| image_caption = ''[[Drosophila melanogaster]]''
| regnum = [[Animal]]ia
| phylum = [[Arthropod]]a
| subphylum = [[Hexapoda]]
| classis = [[Insect]]a
| subclassis = [[Pterygota]]
| infraclassis = [[Neoptera]]
| superordo = [[Endopterygota]]|
| ordo = [[Fly|Diptera]]
| familia = [[Drosophilidae]]
| subfamilia = [[Drosophilinae]]
| genus = '''''Drosophila'''''
| genus_authority = [[Carl Frederick Fallén|Fallén]], 1823
| type_species = ''[[Drosophila funebris]]''
| type_species_authority = ([[Johan Christian Fabricius|Fabricius]], 1787)
}}
'''''Drosophila''''' is a [[genus]] of small [[fly|flies]], belonging to the [[family (biology)|family]] [[Drosophilidae]], whose members are often called "fruit flies" or more appropriately [[vinegar]] flies, [[wine]] flies, [[pomace]] flies, [[grape]] flies, and picked fruit-flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. A second, related fly family, the [[Tephritidae]], are also called fruit flies; these feed primarily on unripe or ripe [[fruit]], with many species being regarded as destructive agricultural pests, especially the [[Mediterranean fruit fly]]. One species of ''Drosophila'' in particular, ''[[Drosophila melanogaster|D. melanogaster]]'', has been heavily used in research in [[genetics]] and is a common [[model organism]] in [[developmental biology]]. Indeed, the terms "fruit fly" and "''Drosophila''" are often used synonymously with ''D. melanogaster'' in modern biological literature. The entire genus, however, contains about 1,500 species and is very diverse in appearance, behavior, and breeding habitat. Scientists who research ''Drosophila'' are often called '''Drosophilists'''.
== Name ==
The term "''Drosophila''", meaning "dew-loving", is a modern scientific [[Latin]] adaptation from [[Greek language|Greek]] words δρόσος, ''drósos'', "[[dew]]", and φίλος, ''phílos'', "loving" with the Latin feminine suffix ''-a''.
==Morphology==
[[Image:Drosophila residua head.jpg|thumb|Side view of head showing characteristic bristles above the eye.]][[Image:Drosophila setosimentum.jpg|thumb|''D. setosimentum'', a species of Hawaiian picture-wing fly.]]
''Drosophila'' are small [[Diptera|flies]], typically pale yellow to reddish brown to black, with red eyes. Many species, including the noted Hawaiian picture-wings, have distinct black patterns on the wings. The plumose (feathery) [[antenna (biology)|arista]], bristling of the head and thorax, and wing venation are characters used to diagnose the family. Most are small, about 2–4 [[millimetre]]s long, but some, especially many of the Hawaiian species, are larger than a [[house fly]].
==Life cycle and ecology==
===Habitat===
''Drosophila'' are found all around the world, with more species in the tropical regions. They can be found in [[deserts]], [[tropical rainforest]], [[cities]], [[swamp]]s, and [[alpine climate|alpine zones]]. Some northern species [[hibernation|hibernate]]. Most species breed in various kinds of decaying plant and [[fungus|fungal]] material, including [[fruit]], [[bark]], [[slime flux]]es, [[flower]]s, and [[mushroom]]s. A few species have switched to being [[parasite]]s or [[predators]]. Many species can be attracted to baits of fermented [[banana]]s or mushrooms, but others are not attracted to any kind of baits. Males may congregate at patches of suitable breeding substrate to compete for the females, or form [[Lek (animal behaviour)|leks]], conducting courtship in an area separate from breeding sites.
Several ''Drosophila'' species, including ''D. melanogaster'', ''D. immigrans'', and [[Drosophila simulans|''D. simulans'']], are closely associated with humans, and are often referred to as [[Domestication|domestic]] species. These and other species (''D. subobscura'', ''Zaprionus indianus'') have been accidentally introduced around the world by human activities such as fruit transports.
===Reproduction===
[[Image:Drosophila egg.png|frame|''Drosophila melanogaster'' egg]]
[[Image:Drosophila eggs Nuuanu.jpg|thumb|right|200px|''Drosophila'' eggs inserted deep in bark, showing the long respiratory filaments.]]
[[Image:Fruit fly larva 01.jpg|thumb|right|200px|''Drosophila'' larva]]
[[Image:Fruit fly pupae 01.jpg|thumb|right|200px|''Drosophila'' pupae – the white ones are young pupae while the brown ones are older.]]
Males of this genus are known to have the longest [[spermatozoon|sperm]] cells of any organism on Earth, including one species, ''[[Drosophila bifurca]]'', that have sperm that are 5.8 [[centimetre]]s long.<ref name="Pitnick">Pitnick, S., G.S. Spicer, T.A. Markow (1995). How long is a giant sperm? ''Nature'' 375:109. PMID 7753164</ref> The cells are mostly tail, and are delivered to the females in tangled coils. The other members of the genus ''Drosophila'' also make relatively few giant sperm cells, with ''D. bifurca's'' being the longest.<ref name="Joly-2007">Joly, D., N. Luck, B. Dejonghe (2007). Adaptation to Long Sperm in Drosophila: Correlated Development of the Sperm Roller and Sperm Packaging. ''Journal of Experimental Zoology (Molecular and Developmental Evolution)'' 308B:DOI: 10.1002/jez.b.21167. PMID 17377954</ref> ''D. melanogaster'' sperm cells are a more modest 1.8 millimetres long, although this is still about 300 times as long as a human sperm.
''Drosophila'' vary widely in their reproductive capacity. Those such as ''D. melanogaster'' that breed in large, relatively rare resources have [[ovaries]] that mature 10–20 eggs at a time, so that they can be laid together on one site. Others that breed in more-abundant but less nutritious substrates, such as leaves, may only lay one egg per day. The eggs have one or more respiratory filaments near the anterior end; the tips of these extend above the surface and allow oxygen to reach the embryo. Larvae feed not on the vegetable matter itself but on the [[yeast]]s and [[microorganism]]s present on the decaying breeding substrate. Development time varies widely between species (between 7 and more than 60 days) and depends on the environmental factors such as [[temperature]], breeding substrate, and crowding.
===Laboratory–cultured animals===
[[Image:EyeColors.jpg|thumb|right|200px|''Drosophila melanogaster'' types. Eye colors (clockwise): brown, cinnabar, sepia, vermilion, white, wild. Also, the wild-eyed fly has a yellow body, the sepia-eyed fly has an ebony body, and the brown-eyed fly has a black body.]]
''Drosophila melanogaster'' is a popular experimental animal because it is easily cultured in mass out of the wild, has a short generation time, and mutant animals are readily obtainable. In 1906 [[Thomas Hunt Morgan]] began his work on ''D. melanogaster'' and reported his first finding of a ''white'' (eyed) mutant in 1910 to the academic community. He was in search of a model organism to study genetic heredity and required a species that could randomly acquire genetic mutation that would visibly manifest as morphological changes in the adult animal. His work on ''Drosophila'' earned him the 1933 [[Nobel Prize]] in Medicine for identifying [[chromosomes]] as the vector of inheritance for genes.
However, some species of ''Drosophila'' are difficult to culture in the laboratory, often because they breed on a single specific host in the wild. For some it can be done with particular recipes for rearing media, or by introducing chemicals such as [[sterols]] that are found in the natural host; for others it is (so far) impossible. In some cases, the larvae can develop on normal ''Drosophila'' lab medium but the female will not lay eggs; for these it is often simply a matter of putting in a small piece of the natural host to receive the eggs. The [http://stockcenter.arl.arizona.edu/ ''Drosophila'' Stock Center] in [[Tucson]] maintains cultures of hundreds of species for researchers.
===Predators===
''Drosophila'' are prey for many generalist predators such as [[Asilidae|robber flies]]. In [[Hawaii]], the introduction of [[Vespula|yellowjackets]] from the mainland [[United States]] has led to the decline of many of the large species. The larvae are preyed on by other fly larvae, [[Staphylinidae|staphylinid]] [[beetles]], and [[ants]].
==Systematics==
The [[genus]] ''Drosophila'' as currently defined is [[paraphyletic]] (see below) and contains 1450 described species,<ref name=taxodros>[[Gerhard Bächli|Bächli, G.]] 1999-2006. [http://taxodros.unizh.ch/ TaxoDros]: The database on Taxonomy of [[Drosophilidae]].</ref><ref>Markow, T. A. and P. M. O'Grady (2006). ''Drosophila'': A guide to species identification and use. [[London]], [[UK]], [[Elsevier Inc.]]</ref> while the estimated total number of species is estimated at thousands.<ref>{{cite book | last = Patterson | first = Colin | title = Evolution | publisher = Cornell University Press | date = 1999 | id = ISBN 0801485940 }}</ref> The majority of the [[species]] are members of two subgenera: ''Drosophila'' (~1,100 species) and ''[[Sophophora]]'' (including ''[[Drosophila melanogaster|D. (S.) melanogaster]]''; ~330 species). The Hawaiian species of ''Drosophila'' (estimated to be more than 500, with ~380 species described) are sometimes recognized as a separate genus or subgenus, ''Idiomyia'',<ref name=taxodros/> but this is not widely accepted. About 250 species are part of the genus ''Scaptomyza'', which arose from the Hawaiian ''Drosophila'' and later re-colonized continental areas.
Evidence from [[phylogenetic]] studies suggests that the following genera arose from within the genus ''Drosophila'':
*''Hirtodrosophila'' <small>Duda, 1923</small>
*''Mycodrosophila'' <small>Oldenburg, 1914</small>
*''Zaprionus'' <small>Coquillett, 1901</small>
*''Samoaia'' <small>Malloch, 1934</small>
*''Liodrosophila'' <small>Duda, 1922</small>
*''Dichaetophora'' <small>Duda, 1940</small>
*''Scaptomyza'' <small>Hardy, 1849</small>
Several of the subgeneric and generic names are based on anagrams of ''Drosophila''. These include:
*''Dorsilopha''
*''Lordiphosa''
*''Siphlodora''
*''Phloridosa''
*''Psilodorha''
==''Drosophila'' species genome project==
''Drosophila'' are extensively used as a model organism in genetics (including population genetics), cell-biology, biochemistry, and especially developmental biology. Therefore, extensive efforts are made to sequence drosphilid genomes. The genomes of the following species have been fully or partially sequenced so far:
*''[[Drosophila melanogaster|Drosophila (Sophophora) melanogaster]]''<ref>http://rana.lbl.gov/drosophila/melanogaster.html</ref>
*''[[Drosophila simulans|Drosophila (Sophophora) simulans]]''<ref>http://rana.lbl.gov/drosophila/simulans.html</ref>
*''[[Drosophila melanogaster species subgroup|Drosophila (Sophophora) sechellia]]''<ref>http://rana.lbl.gov/drosophila/sechellia.html</ref>
*''[[Drosophila melanogaster species subgroup|Drosophila (Sophophora) yakuba]]''<ref>http://rana.lbl.gov/drosophila/yakuba.html</ref>
*''[[Drosophila melanogaster species subgroup|Drosophila (Sophophora) erecta]]''<ref>http://rana.lbl.gov/drosophila/erecta.html</ref>
*''[[Drosophila melanogaster species group|Drosophila (Sophophora) ananassae]]''<ref>http://rana.lbl.gov/drosophila/ananassae.html</ref>
*''[[Drosophila pseudoobscura|Drosophila (Sophophora) pseudoobscura]]''<ref>http://rana.lbl.gov/drosophila/pseudoobscura.html</ref>
*''Drosophila (Sophophora) persimilis''<ref>http://rana.lbl.gov/drosophila/persimilis.html</ref>
*''Drosophila (Sophophora) willistoni''<ref>http://rana.lbl.gov/drosophila/willistoni.html</ref>
*''Drosophila (Drosophila) mojavensis''<ref>http://rana.lbl.gov/drosophila/mojavensis.html</ref>
*''Drosophila (Drosophila) virilis''<ref>http://rana.lbl.gov/drosophila/virilis.html</ref>
*''Drosophila (Drosophila) grimshawi''<ref>http://rana.lbl.gov/drosophila/grimshawi.html</ref>
The data will be used for many purposes, including evolutionary genome comparisons. ''D. simulans'' and ''D. sechellia'' are sister species, and provide viable offspring when crossed, while ''D. melanogaster'' and ''D. simulans'' produce infertile [[Hybrid (biology)|hybrid]] offspring. The ''Drosophila'' genome is often compared with the genomes of more distantly related species such as the [[honeybee]] ''[[Western honeybee|Apis mellifera]]'' or the [[mosquito]] ''[[Anopheles gambiae]]''.
Curated data are available at [[FlyBase]].
==See also==
*[[Drosophila embryogenesis]]
*[[Insect Habitat]]
==External links==
*[http://flybase.bio.indiana.edu/ Fly Base] FlyBase is a comprehensive database for information on the genetics and molecular biology of Drosophila. It includes data from the Drosophila Genome Projects and data curated from the literature.
*[http://www.fruitfly.org/ Berkeley Drosophila Genome Project]
*[http://rana.lbl.gov/drosophila/ AAA]: Assembly, Alignment and Annotation of 12 Drosophila species
*[http://genome.ucsc.edu/cgi-bin/hgGateway UCSC Genome browser]
*[http://taxodros.unizh.ch/ TaxoDros: The database on Taxonomy of Drosophilidae]
*[http://stockcenter.arl.arizona.edu/ Tucson ''Drosophila'' Stock Center] breeds hundreds of species and supplies them to researchers
*[http://www.flymine.org FlyMine] is an integrated database of genomic, expression and protein data for Drosophila
==References==
{{reflist}}
{{Model Organisms}}
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